Front	Rear

Side	Open for Rigging

Technical Details

Bill Varnedoe gave me this descender in August 2000. He didn't know the history behind it; however, we believe it dates from the 1960’s.

The frame is made from two 3/8" by 1" by 4-1/2" (9.8 mm. by 25.4 mm. by 112.8 mm.) pieces of aluminum, probably 6061-T6. These are connected by two 1/2" (12.7 mm.) and one 3/8" (9.8 mm.) aluminum rods that fit into holes frilled part-way through the side pieces. The rods are pinned to one of the frame pieces. When assembled, the side pieces are 32.5 mm. apart (inside dimension). The cam is a piece of 1-1/4" (31.8 mm.) aluminum rod drilled off-center, and mounted on a 5/16" (8 mm.) stainless steel bolt. The head of the bolt was cut off, and pressed into one of the frame pieces where it was pinned in place. A second pin passes through the bolt to hold the cam in place. A wing nut secures the assembly, and the bolt threads have been mangled so that the wing nut will not come off. A lever made from 1/4" by 3/4" (6.4 mm. by 19.2 mm.) aluminum fits in a slot milled into the cam. A 1/2" (12.7 mm.) hole is drilled in the end of the lever.

Comments

Rappelling with this device is interesting. There is no room to clip in with a carabiner, so a sling must be available. There is considerable friction when it is used on 11 mm. rope, which is close to the limit on what will fit. The lever must be pushed upward to descend. If the lever is released, rope friction turns the cam in the direction that will stop the descent.